I'm sure folks are getting tired of hearing about my proposed cat
project.   I'm still sort of going in circles as far as deciding exactly
what to build, and have acquired several sets of study plans.   The boat
that comes closes to fitting my criteria "out of the box" so to speak,
is the Woods  Sagitta, which unfortunately due to it's cedar strip hull
and knuckle, does not lend itself well to any sort of "intelligent
infusion".  There is no "easy way".  The choices are to build using
strip planked foam (or cedar), hand finishing, and infusing the interior
and exterior separately, or building a half hull plug, hand finished,
and pulling a female mold off that............ NOT an attractive
proposition, and one that would require a huge amount of labor that
could only be justified by molding multiple hulls from that.........
Something I have no desire to do.  I want to build a boat, not a business!

    In looking at  Richard Woods designs, I stumbled across an
interesting thing.    Two boats that are in his description essentially
the same boat, one in cedar strip (hull and cabin top), and one in
plywood.   The cedar strip boat was 12.5% lighter than the plywood
boat.   The boats are the next size up from what I'm looking at.  
Slightly different in length due to different bow shape, and ranging
from 14" longer to 2' longer than Sagitta.   The shorter boat (Tamar),
at 14" longer than Sagitta and very similar in many ways is 1200kg
(2640) heavier than Sagitta, offering nothing that is of interest to me
except 300kg additional payload.  It is of plywood.   The Eclipse being
the longer of the two is lighter than Tamar by 250kg, and the only thing
I can point to that would explain the difference is plywood construction.

    The implication here is that cedar strip construction offers about
half as much weight reduction potential as infused foam sandwich, at a
far lower cost in terms of materials (here), but a far higher cost in
terms of labor (presumably)  That suggests that the potential savings on
Sagitta's empty weight using strip plank infused foam and infused foam
panels as compared to strip planked cedar and plywood should only range
somewhere between 135kg and 225kg (about 300-500 pounds).  That hardly
justifies the additional cost in materials (all else aside)

                              *********************************

    On a parallel track, I've been working out how to stretch the KD860
to 30' without getting into a lot of highly complex calculations,
etc.    It is not a simple matter of adding a percentage between each
bulkhead or some such strategy, as the construction is flat sheet, and
the end result is that the skin must lay properly on the bulkheads. 
Essentially the hull sides must be some part of a theoretical cone
shape.    The process begins with laying out the flat hull bottom at a
reduced scale. For convenience 10%, maintaining the straight slope of
the forward end, and very slightly increasing the aft radius, setting up
the widths as appropriate at the bulkheads, and using  a piece of light
weight plywood or heavy construction board to adjust and ensure that
everything lays properly.  The bottom as laid consists of horizontal
sticks where the bulkheads will be, and a vertical central rib at right
angles to each of these members gives a reference to work from.    Once
the bottom is laid, construction board is laid against the bottom
members, and flared to the desired width at the sheer line from bow to
stern.  Once the desired shape is achieved and made fair, verticals and
horizontals are added at each bulkhead location, creating half bulkhead
templates to scale.  Actual scale bulkheads are made from these and
mounted inverted, using a strongback screwed to the workbench, and the
actual scale model made from them.  Once a satisfactory result is
achieved, the 10% bulkheads can easily be scaled up to full size.

    As I'm not actually ready to build the boat, I have plenty of time
to mess about with this.   I don't do TV, etc, so my spare time is
dedicated to projects anyway.   It's my nature to work with my hands and
brain, and calculator.   I'm not quite set up to do this model project
yet..... I intend to build a project table specific to this model.     I
tend to spend a lot of thought time, working out the methods before
cutting wood.    In the end I've found that this saves me a lot of time
going down "blind alleys" and redoing things.

H.W.